men_with_ties
New Member
Dear forum members;
We are building a number of stereo amplifiers based on the LM386 chip. The amps are using electret microphones with a bias resistor (+5v), and are based on the standard 200x amplification circuit from the National 386 datasheet. We are driving (pretty mediocre) 8-ohm, 1/4-watt speakers.
Unfortunately, we are experiencing substantial crosstalk; signals from the microphones are being picked up by both amplifiers at near-equal volume levels. We seem to be having leakage through the grounds. My suspicion is that we need to do power supply filtering, as it seems highly plausible that the current draw from one speaker is leaking through the circuit and being perceived as an audio signal by the other amplifier chip.
Does anyone have experience in successfully building stereo LM386 circuits? Any knowledge to share? Your expertise is gratefully welcomed! I will post a schematic of our circuit shortly; I'll need to draw it up.
Best regards,
men_with_ties
We are building a number of stereo amplifiers based on the LM386 chip. The amps are using electret microphones with a bias resistor (+5v), and are based on the standard 200x amplification circuit from the National 386 datasheet. We are driving (pretty mediocre) 8-ohm, 1/4-watt speakers.
Unfortunately, we are experiencing substantial crosstalk; signals from the microphones are being picked up by both amplifiers at near-equal volume levels. We seem to be having leakage through the grounds. My suspicion is that we need to do power supply filtering, as it seems highly plausible that the current draw from one speaker is leaking through the circuit and being perceived as an audio signal by the other amplifier chip.
Does anyone have experience in successfully building stereo LM386 circuits? Any knowledge to share? Your expertise is gratefully welcomed! I will post a schematic of our circuit shortly; I'll need to draw it up.
Best regards,
men_with_ties